Data unit receiver and sender control method

Abstract

A method is described for controlling a data unit receiver or a data unit sender. The data unit receiver or sender comprise a gap response procedure for responding to gaps in the sequence of data units received at the receiver. A reordering detection procedure S12 is provided for detecting a reordering indication indicative of a potential re-ordering of data units in the course of a transmission from sender to receiver, and the gap response procedure is adapted in response to detecting a re-ordering indication.

Description

FIELD OF THE INVENTION[0001]The present application relates to a method of controlling a data unit receiver, a method of controlling a data unit sender and to corresponding data unit receivers and senders.BACKGROUND OF THE INVENTION[0002]The present invention generally relates to the field of communication via data unit transmission. In a data unit communication, a stream of data symbols (e.g. bits or bytes) is divided by a sender into units, sent over an appropriate transmission network to a receiver, and the receiver reconstructs the data symbol stream on the basis of the received data units. Usually, this is performed in the context of a layering scheme, such as the OSI scheme, i.e. where a sending peer of a given protocol receives a data symbol stream from a higher layer, generates data units in accordance with the given protocol to which the sending peer adheres, and passes the generated data units to lower layers. On the receiving side, the receiving peer receives the data uni...

AI Technical Summary

Benefits of technology

[0011]In other words, by explicitly looking out for a reordering indication and appropriately adapting the gap detection and response procedure at the receiver and / or the gap response procedure at the sender, one may greatly improve the performance over the prior art, in which it was always assumed that the data units should arrive in the same order as they were sent, such that a gap will always primarily be attributable to a data unit loss. By monitoring for and detecting reordering indications, the present invention can make the data unit receiver and / or sender explicitly aware of a reordering, such that the receiver and / or sender can change their response by then assuming that a gap is primarily due to a reordering. By therefore responding more appropriately to the most probable reason for the gap, the overall performance can be improved.

[0016]As an alternative for a sender that employs a gap response procedure with a DUPACK threshold, it is possible to increase the DUPACK threshold as a response to detecting a reordering indication.

[0017]On the side of the data unit receiver, the adapting of the gap detection and response procedure preferably consists in dividing the received data units into at least two groups in dependence on the reordering indication, and then applying the gap detection and response procedure separately to the two groups. “Separately” means that the receiver looks for a gap within each group, but not between the groups. Such a mechanism is better than completely disabling the gap detection and response, but avoids responding to a gap that can most probably be attributed to a reordering and not to a data unit loss.

Problems solved by technology

Reordering is a phenomenon in which a later sent data unit overtakes a previously sent data unit, e.g. because the previously sent data unit is excessively delayed in the network.

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